Delay spread and average delay quasi-collocation sources for positioning reference signals

ABSTRACT

Disclosed are techniques for receiving reference radio frequency (RF) signals for positioning estimation. In an aspect, a receiver device receives, from a transmission point, a reference RF signal on a wireless channel receives, from a positioning entity, an indication that the reference RF signal serves as a source for a quasi-collocation (QCL) type(s) for positioning reference RF signals received by the receiver device from the transmission point on the wireless channel, measures an average delay, a delay spread, or both the average delay and the delay spread of the reference RF signal based on the QCL type(s), receives, from the transmission point, a positioning reference RF signal on the wireless channel, and identifies a time of arrival (ToA) of the positioning reference RF signal based on the measured average delay, the delay spread, or both the average delay and the delay spread of the reference RF signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application for Patent claims priority under 35 U.S.C. § 119to Greek Patent Application No. 20180100462, entitled “DELAY SPREAD ANDAVERAGE DELAY QUASI-COLLOCATION SOURCES FOR POSITIONING REFERENCESIGNALS,” filed Oct. 5, 2018, assigned to the assignee hereof, andexpressly incorporated herein by reference in its entirety.

TECHNICAL FIELD

Various aspects described herein generally relate to wirelesscommunication systems, and more particularly, to delay spread andaverage delay quasi-collocation sources for positioning referencesignals.

BACKGROUND

Wireless communication systems have developed through variousgenerations, including a first-generation analog wireless phone service(1G), a second-generation (2G) digital wireless phone service (includinginterim 2.5G and 2.75G networks), a third-generation (3G) high speeddata, Internet-capable wireless service and a fourth-generation (4G)service (e.g., Long Term Evolution (LTE) or WiMax). There are presentlymany different types of wireless communication systems in use, includingcellular and personal communications service (PCS) systems. Examples ofknown cellular systems include the cellular Analog Advanced Mobile PhoneSystem (AMPS), and digital cellular systems based on code divisionmultiple access (CDMA), frequency division multiple access (FDMA), timedivision multiple access (TDMA), the Global System for Mobile access(GSM) variation of TDMA, etc.

A fifth generation (5G) mobile standard calls for higher data transferspeeds, greater numbers of connections, and better coverage, among otherimprovements. The 5G standard, according to the Next Generation MobileNetworks Alliance, is designed to provide data rates of several tens ofmegabits per second to each of tens of thousands of users, with 1gigabit per second to tens of workers on an office floor. Severalhundreds of thousands of simultaneous connections should be supported inorder to support large sensor deployments. Consequently, the spectralefficiency of 5G mobile communications should be significantly enhancedcompared to the current 4G standard. Furthermore, signaling efficienciesshould be enhanced and latency should be substantially reduced comparedto current standards.

To support position estimations in terrestrial wireless networks, amobile device can be configured to measure and report the observed timedifference of arrival (OTDOA) or reference signal timing difference(RSTD) between reference radio frequency (RF) signals received from twoor more network nodes (e.g., different base stations or differenttransmission points (e.g., antennas) belonging to the same basestation).

SUMMARY

The following presents a simplified summary relating to one or moreaspects disclosed herein. As such, the following summary should not beconsidered an extensive overview relating to all contemplated aspects,nor should the following summary be regarded to identify key or criticalelements relating to all contemplated aspects or to delineate the scopeassociated with any particular aspect. Accordingly, the followingsummary has the sole purpose to present certain concepts relating to oneor more aspects relating to the mechanisms disclosed herein in asimplified form to precede the detailed description presented below.

In an aspect, a method for receiving reference RF signals forpositioning estimation includes receiving, at a receiver device from atransmission point, a reference RF signal on a wireless channel;receiving, at the receiver device from a positioning entity, anindication that the reference RF signal serves as a source for aquasi-collocation (QCL) type(s) for positioning reference RF signalsreceived by the receiver device from the transmission point on thewireless channel; measuring, by the receiver device, an average delay, adelay spread, or both the average delay and the delay spread of thesource reference RF signal based on the QCL type(s); receiving, at thereceiver device from the transmission point, a positioning reference RFsignal on the wireless channel; and identifying, by the receiver device,a time of arrival (ToA) of the positioning reference RF signal based onthe measured average delay, the delay spread, or both of the referenceRF signal.

In an aspect, a method of wireless communication performed by atransmission point includes transmitting, to a receiver device, areference RF signal on a wireless channel; transmitting, to the receiverdevice, an indication that the reference RF signal serves as a sourcefor a QCL type(s) for positioning reference RF signals received by thereceiver device from the transmission point on the wireless channel; andtransmitting, to the receiver device, a positioning reference RF signalon the wireless channel according to the QCL type(s), wherein the QCLtype(s) indicates that the reference RF signal and the positioningreference RF signal have the same average delay only, the same delayspread only, or both the same average delay and the same delay spread.

In an aspect, an apparatus for wireless communication includes at leastone receiver of a receiver device configured to: receive, from atransmission point, a reference RF signal on a wireless channel; andreceive, from a positioning entity, an indication that the reference RFsignal serves as a source for a QCL type(s) for positioning reference RFsignals received by the receiver device from the transmission point onthe wireless channel; and at least one processor of the receiver deviceconfigured to: measure an average delay, a delay spread, or both theaverage delay and the delay spread of the source reference RF signalbased on the QCL type(s), wherein the at least one receiver is furtherconfigured to receive, from the transmission point, a positioningreference RF signal on the wireless channel, and wherein the at leastone processor is further configured to identify a ToA of the positioningreference RF signal based on the measured average delay, the delayspread, or both the average delay and the delay spread of the referenceRF signal.

In an aspect, an apparatus for wireless communication includes atransmitter of a transmission point configured to: transmit, to areceiver device, a reference RF signal on a wireless channel; transmit,to the receiver device, an indication that the reference RF signalserves as a source for a QCL type(s) for positioning reference RFsignals received by the receiver device from the transmission point onthe wireless channel; and transmit, to the receiver device, apositioning reference RF signal on the wireless channel according to theQCL type(s), wherein the QCL type(s) indicates that the reference RFsignal and the positioning reference RF signal have the same averagedelay only, the same delay spread only, or both the same average delayand the same delay spread.

In an aspect, an apparatus for wireless communication includes means forreceiving, at a receiver device from a transmission point, a referenceRF signal on a wireless channel; means for receiving, at the receiverdevice from a positioning entity, an indication that the reference RFsignal serves as a source for a QCL type(s) for positioning reference RFsignals received by the receiver device from the transmission point onthe wireless channel; means for measuring, by the receiver device, anaverage delay, a delay spread, or both the average delay and the delayspread of the reference RF signal based on the QCL type(s); means forreceiving, at the receiver device from the transmission point, apositioning reference RF signal on the wireless channel; and means foridentifying, by the receiver device, a ToA of the positioning referenceRF signal based on the measured average delay, the delay spread, or boththe average delay and the delay spread of the reference RF signal.

In an aspect, an apparatus for wireless communication includes means fortransmitting, to a receiver device, a reference RF signal on a wirelesschannel; means for transmitting, to the receiver device, an indicationthat the reference RF signal serves as a source for a QCL type(s) forpositioning reference RF signals received by the receiver device fromthe transmission point on the wireless channel; and means fortransmitting, to the receiver device, a positioning reference RF signalon the wireless channel according to the QCL type(s), wherein the QCLtype(s) indicates that the reference RF signal and the positioningreference RF signal have the same average delay only, the same delayspread only, or both the same average delay and the same delay spread.

In an aspect, a non-transitory computer-readable medium storingcomputer-executable instructions for wireless communication includescomputer-executable instructions comprising: at least one instructioninstructing a receiver device to receive, from a transmission point, areference RF signal on a wireless channel; at least one instructioninstructing the receiver device to receive, from a positioning entity,an indication that the reference RF signal serves as a source for a QCLtype(s) for positioning reference RF signals received by the receiverdevice from the transmission point on the wireless channel; at least oneinstruction instructing the receiver device to measure an average delay,a delay spread, or both the average delay and the delay spread of thereference RF signal based on the QCL type(s); at least one instructioninstructing the receiver device to receive, from the transmission point,a positioning reference RF signal on the wireless channel; and at leastone instruction instructing the receiver device to identify a ToA of thepositioning reference RF signal based on the measured average delay, thedelay spread, or both the average delay and the delay spread of thereference RF signal.

In an aspect, a non-transitory computer-readable medium storingcomputer-executable instructions for wireless communication includescomputer-executable instructions comprising: transmitting, to a receiverdevice, a reference RF signal on a wireless channel; transmitting, tothe receiver device, an indication that the reference RF signal servesas a source for a QCL type(s) for positioning reference RF signalsreceived by the receiver device from the transmission point on thewireless channel; and transmitting, to the receiver device, apositioning reference RF signal on the wireless channel according to theQCL type(s), wherein the QCL type(s) indicates that the reference RFsignal and the positioning reference RF signal have the same averagedelay only, the same delay spread only, or both the same average delayand the same delay spread.

Other objects and advantages associated with the aspects disclosedherein will be apparent to those skilled in the art based on theaccompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the various aspects described herein andmany attendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanying drawingswhich are presented solely for illustration and not limitation, and inwhich:

FIG. 1 illustrates an exemplary wireless communications system,according to aspects of the disclosure.

FIGS. 2A and 2B illustrate example wireless network structures,according to aspects of the disclosure.

FIG. 3 illustrates an exemplary base station and an exemplary UE in anaccess network, according to aspects of the disclosure.

FIG. 4 is a diagram illustrating an exemplary technique for determininga position of a mobile device using information obtained from aplurality of base stations, according to aspects of the disclosure.

FIGS. 5A and 5B illustrate graphs of exemplary channel energy responses(CERs), according to aspects of the disclosure.

FIG. 6 is a graph comparing a cumulative distribution function (CDF) toa distance error for all initializations across all UEs of a particularsample set, according to aspects of the disclosure.

FIGS. 7 to 8B are graphs of exemplary CER estimates, according toaspects of the disclosure

FIG. 9 illustrates how cyclic shift changes the average delay of awireless channel, according to aspects of the disclosure.

FIGS. 10 and 11 illustrate exemplary methods for wireless communication,according to aspects of the disclosure.

DETAILED DESCRIPTION

Various aspects described herein generally relate to wirelesscommunication systems, and more particularly, to delay spread andaverage delay quasi-collocation sources for positioning referencesignals in 5G NR and associated transmission parameters. These and otheraspects are disclosed in the following description and related drawingsto show specific examples relating to exemplary aspects. Alternateaspects will be apparent to those skilled in the pertinent art uponreading this disclosure, and may be constructed and practiced withoutdeparting from the scope or spirit of the disclosure. Additionally,well-known elements will not be described in detail or may be omitted soas to not obscure the relevant details of the aspects disclosed herein.

The words “exemplary” and/or “example” are used herein to mean “servingas an example, instance, or illustration.” Any aspect described hereinas “exemplary” and/or “example” is not necessarily to be construed aspreferred or advantageous over other aspects. Likewise, the term“aspects of the disclosure” does not require that all aspects of thedisclosure include the discussed feature, advantage or mode ofoperation.

The terminology used herein describes particular aspects only and shouldnot be construed to limit any aspects disclosed herein. As used herein,the singular forms “a,” “an,” and “the” are intended to include theplural forms as well, unless the context clearly indicates otherwise.Those skilled in the art will further understand that the terms“comprises,” “comprising,” “includes,” and/or “including,” as usedherein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Those of skill in the art will appreciate that the information andsignals described below may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the description below may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof, depending inpart on the particular application, in part on the desired design, inpart on the corresponding technology, etc.

Further, many aspects are described in terms of sequences of actions tobe performed by, for example, elements of a computing device. It will berecognized that various actions described herein can be performed byspecific circuits (e.g., application specific integrated circuits(ASICs)), by program instructions being executed by one or moreprocessors, or by a combination of both. Additionally, the sequence(s)of actions described herein can be considered to be embodied entirelywithin any form of non-transitory computer-readable storage mediumhaving stored therein a corresponding set of computer instructions that,upon execution, would cause or instruct an associated processor of adevice to perform the functionality described herein. Thus, the variousaspects of the disclosure may be embodied in a number of differentforms, all of which have been contemplated to be within the scope of theclaimed subject matter. In addition, for each of the aspects describedherein, the corresponding form of any such aspects may be describedherein as, for example, “logic configured to” perform the describedaction.

As used herein, the terms “user equipment” (UE) and “base station” arenot intended to be specific or otherwise limited to any particular RadioAccess Technology (RAT), unless otherwise noted. In general, a UE may beany wireless communication device (e.g., a mobile phone, router, tabletcomputer, laptop computer, tracking device, wearable (e.g., smartwatch,glasses, augmented reality (AR)/virtual reality (VR) headset, etc.),vehicle (e.g., automobile, motorcycle, bicycle, etc.), Internet ofThings (IoT) device, etc.) used by a user to communicate over a wirelesscommunications network. A UE may be mobile or may (e.g., at certaintimes) be stationary, and may communicate with a Radio Access Network(RAN). As used herein, the term “UE” may be referred to interchangeablyas an “access terminal” or “AT,” a “client device,” a “wireless device,”a “subscriber device,” a “subscriber terminal,” a “subscriber station,”a “user terminal” or UT, a “mobile terminal,” a “mobile station,” orvariations thereof. Generally, UEs can communicate with a core networkvia a RAN, and through the core network the UEs can be connected withexternal networks such as the Internet and with other UEs. Of course,other mechanisms of connecting to the core network and/or the Internetare also possible for the UEs, such as over wired access networks,wireless local area network (WLAN) networks (e.g., based on IEEE 802.11,etc.) and so on.

A base station may operate according to one of several RATs incommunication with UEs depending on the network in which it is deployed,and may be alternatively referred to as an access point (AP), a networknode, a NodeB, an evolved NodeB (eNB), a New Radio (NR) Node B (alsoreferred to as a gNB or gNodeB), etc. In addition, in some systems abase station may provide purely edge node signaling functions while inother systems it may provide additional control and/or networkmanagement functions. A communication link through which UEs can sendsignals to a base station is called an uplink (UL) channel (e.g., areverse traffic channel, a reverse control channel, an access channel,etc.). A communication link through which the base station can sendsignals to UEs is called a downlink (DL) or forward link channel (e.g.,a paging channel, a control channel, a broadcast channel, a forwardtraffic channel, etc.). As used herein the term traffic channel (TCH)can refer to either an UL/reverse or DL/forward traffic channel.

According to various aspects, FIG. 1 illustrates an exemplary wirelesscommunications system 100. The wireless communications system 100 (whichmay also be referred to as a wireless wide area network (WWAN)) mayinclude various base stations 102 and various UEs 104. The base stations102 may include macro cell base stations (high power cellular basestations) and/or small cell base stations (low power cellular basestations). In an aspect, the macro cell base station may include eNBswhere the wireless communications system 100 corresponds to an LTEnetwork, or gNBs where the wireless communications system 100corresponds to a 5G network, or a combination of both, and the smallcell base stations may include femtocells, picocells, microcells, etc.

The base stations 102 may collectively form a RAN and interface with acore network 170 (e.g., an evolved packet core (EPC) or next generationcore (NGC)) through backhaul links 122, and through the core network 170to one or more location servers 172. In addition to other functions, thebase stations 102 may perform functions that relate to one or more oftransferring user data, radio channel ciphering and deciphering,integrity protection, header compression, mobility control functions(e.g., handover, dual connectivity), inter-cell interferencecoordination, connection setup and release, load balancing, distributionfor non-access stratum (NAS) messages, NAS node selection,synchronization, RAN sharing, multimedia broadcast multicast service(MBMS), subscriber and equipment trace, RAN information management(RIM), paging, positioning, and delivery of warning messages. The basestations 102 may communicate with each other directly or indirectly(e.g., through the EPC/NGC) over backhaul links 134, which may be wiredor wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. In an aspect, one or more cellsmay be supported by a base station 102 in each coverage area 110. A“cell” is a logical communication entity used for communication with abase station (e.g., over some frequency resource, referred to as acarrier frequency, component carrier, carrier, band, or the like), andmay be associated with an identifier (e.g., a physical cell identifier(PCID), a virtual cell identifier (VCID)) for distinguishing cellsoperating via the same or a different carrier frequency. In some cases,different cells may be configured according to different protocol types(e.g., machine-type communication (MTC), narrowband IoT (NB-IoT),enhanced mobile broadband (eMBB), or others) that may provide access fordifferent types of UEs. In some cases, the term “cell” may also refer toa geographic coverage area of a base station (e.g., a sector), insofaras a carrier frequency can be detected and used for communication withinsome portion of geographic coverage areas 110.

While neighboring macro cell base station 102 geographic coverage areas110 may partially overlap (e.g., in a handover region), some of thegeographic coverage areas 110 may be substantially overlapped by alarger geographic coverage area 110. For example, a small cell basestation 102′ may have a coverage area 110′ that substantially overlapswith the coverage area 110 of one or more macro cell base stations 102.A network that includes both small cell and macro cell base stations maybe known as a heterogeneous network. A heterogeneous network may alsoinclude home eNBs (HeNBs), which may provide service to a restrictedgroup known as a closed subscriber group (CSG).

The communication links 120 between the base stations 102 and the UEs104 may include UL (also referred to as reverse link) transmissions froma UE 104 to a base station 102 and/or downlink (DL) (also referred to asforward link) transmissions from a base station 102 to a UE 104. Thecommunication links 120 may use MIMO antenna technology, includingspatial multiplexing, beamforming, and/or transmit diversity. Thecommunication links 120 may be through one or more carrier frequencies.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or less carriers may be allocated for DL than for UL).

The wireless communications system 100 may further include a wirelesslocal area network (WLAN) access point (AP) 150 in communication withWLAN stations (STAs) 152 via communication links 154 in an unlicensedfrequency spectrum (e.g., 5 GHz). When communicating in an unlicensedfrequency spectrum, the WLAN STAs 152 and/or the WLAN AP 150 may performa clear channel assessment (CCA) prior to communicating in order todetermine whether the channel is available.

The small cell base station 102′ may operate in a licensed and/or anunlicensed frequency spectrum. When operating in an unlicensed frequencyspectrum, the small cell base station 102′ may employ LTE or 5Gtechnology and use the same 5 GHz unlicensed frequency spectrum as usedby the WLAN AP 150. The small cell base station 102′, employing LTE/5Gin an unlicensed frequency spectrum, may boost coverage to and/orincrease capacity of the access network. LTE in an unlicensed spectrummay be referred to as LTE-unlicensed (LTE-U), licensed assisted access(LAA), or MulteFire.

The wireless communications system 100 may further include a millimeterwave (mmW) base station 180 that may operate in mmW frequencies and/ornear mmW frequencies in communication with a UE 182. Extremely highfrequency (EHF) is part of the RF in the electromagnetic spectrum. EHFhas a range of 30 GHz to 300 GHz and a wavelength between 1 millimeterand 10 millimeters. Radio waves in this band may be referred to as amillimeter wave. Near mmW may extend down to a frequency of 3 GHz with awavelength of 100 millimeters. The super high frequency (SHF) bandextends between 3 GHz and 30 GHz, also referred to as centimeter wave.Communications using the mmW/near mmW radio frequency band have highpath loss and a relatively short range. The mmW base station 180 and theUE 182 may utilize beamforming (transmit and/or receive) over a mmWcommunication link 184 to compensate for the extremely high path lossand short range. Further, it will be appreciated that in alternativeconfigurations, one or more base stations 102 may also transmit usingmmW or near mmW and beamforming. Accordingly, it will be appreciatedthat the foregoing illustrations are merely examples and should not beconstrued to limit the various aspects disclosed herein.

Transmit beamforming is a technique for focusing an RF signal in aspecific direction. Traditionally, when a network node (e.g., a basestation) broadcasts an RF signal, it broadcasts the signal in alldirections (omni-directionally). With transmit beamforming, the networknode determines where a given target device (e.g., a UE) is located(relative to the transmitting network node) and projects a strongerdownlink RF signal in that specific direction, thereby providing afaster (in terms of data rate) and stronger RF signal for the receivingdevice(s). To change the directionality of the RF signal whentransmitting, a network node can control the phase and relativeamplitude of the RF signal at each of the one or more transmitters thatare broadcasting the RF signal. For example, a network node may use anarray of antennas (referred to as a “phased array” or an “antennaarray”) that creates a beam of RF waves that can be “steered” to pointin different directions, without actually moving the antennas.Specifically, the RF current from the transmitter is fed to theindividual antennas with the correct phase relationship so that theradio waves from the separate antennas add together to increase theradiation in a desired direction, while cancelling to suppress radiationin undesired directions.

In receive beamforming, the receiver uses a receive beam to amplify RFsignals detected on a given channel. For example, the receiver canincrease the gain setting and/or adjust the phase setting of an array ofantennas in a particular direction to amplify (e.g., to increase thegain level of) the RF signals received from that direction. Thus, when areceiver is said to beamform in a certain direction, it means the beamgain in that direction is high relative to the beam gain along otherdirections, or the beam gain in that direction is the highest comparedto the beam gain in that direction of all other receive beams availableto the receiver. This results in a stronger received signal strength(e.g., reference signal received power (RSRP), reference signal receivedquality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) ofthe RF signals received from that direction.

An “RF signal” comprises an electromagnetic wave that transportsinformation through the space between a transmitter (e.g., base station102) and a receiver (e.g., UE 104). As used herein, a transmitter maytransmit a single “RF signal” or multiple “RF signals” to a receiver.However, the receiver may receive multiple “RF signals” corresponding toeach transmitted RF signal due to the propagation characteristics of RFsignals through multipath channels. The same transmitted RF signal ondifferent paths between the transmitter and receiver may be referred toas a “multipath” RF signal. An RF signal may also be referred to hereinas simply a “signal.”

Reference RF signals, such as positioning reference signals (PRS) andnavigation reference signals (NRS), may be transmitted on multipleresource elements (REs) of a slot (e.g., 0.5 ms) of a subframe (e.g., 1ms) of a radio frame (e.g., 10 ms). An RE is a time-frequency resourceof one subcarrier (also referred to as a “tone”) in the frequency domainand one orthogonal frequency division multiplexing (OFDM) symbol in thetime domain. A slot may be divided into, for example, seven OFDM symbolsin the time domain. An OFDM symbol/slot/subframe/frame may be dividedinto, for example, 12 subcarriers, or tones, in the frequency domain. Ifa reference RF signal is transmitted on each tone of an OFDM symbol, itis referred to as comb-1, and if it is transmitted on every fourth toneof an OFDM symbol, it is referred to as comb-4.

In 5G, the frequency spectrum in which wireless nodes (e.g., basestations 102/180, UEs 104/182) operate is divided into multiplefrequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In amulti-carrier system, such as 5G, one of the carrier frequencies isreferred to as the “primary carrier” or “anchor carrier” or “primaryserving cell” or “PCell,” and the remaining carrier frequencies arereferred to as “secondary carriers” or “secondary serving cells” or“SCells.” In carrier aggregation, the anchor carrier is the carrieroperating on the primary frequency (e.g., FR1) utilized by a UE 104/182and the cell in which the UE 104/182 either performs the initial radioresource control (RRC) connection establishment procedure or initiatesthe RRC connection re-establishment procedure. The primary carriercarries all common and UE-specific control channels. A secondary carrieris a carrier operating on a second frequency (e.g., FR2) that may beconfigured once the RRC connection is established between the UE 104 andthe anchor carrier and that may be used to provide additional radioresources. The secondary carrier may contain only necessary signalinginformation and signals, for example, those that are UE-specific may notbe present in the secondary carrier, since both primary uplink anddownlink carriers are typically UE-specific. This means that differentUEs 104/182 in a cell may have different downlink primary carriers. Thesame is true for the uplink primary carriers. The network is able tochange the primary carrier of any UE 104/182 at any time. This is done,for example, to balance the load on different carriers. Because a“serving cell” (whether a PCell or an SCell) corresponds to a carrierfrequency/component carrier over which some base station iscommunicating, the term “cell,” “serving cell,” “component carrier,”“carrier frequency,” and the like can be used interchangeably.

For example, still referring to FIG. 1, one of the frequencies utilizedby the macro cell base stations 102 may be an anchor carrier (or“PCell”) and other frequencies utilized by the macro cell base stations102 and/or the mmW base station 180 may be secondary carriers(“SCells”). The simultaneous transmission and/or reception of multiplecarriers enables the UE 104/182 to significantly increase its datatransmission and/or reception rates. For example, two 20 MHz aggregatedcarriers in a multi-carrier system would theoretically lead to atwo-fold increase in data rate (i.e., 40 MHz), compared to that attainedby a single 20 MHz carrier.

The wireless communications system 100 may further include one or moreUEs, such as UE 190, that connects indirectly to one or morecommunication networks via one or more device-to-device (D2D)peer-to-peer (P2P) links. In the example of FIG. 1, UE 190 has a D2D P2Plink 192 with one of the UEs 104 connected to one of the base stations102 (e.g., through which UE 190 may indirectly obtain cellularconnectivity) and a D2D P2P link 194 with WLAN STA 152 connected to theWLAN AP 150 (through which UE 190 may indirectly obtain WLAN-basedInternet connectivity). In an example, the D2D P2P links 192 and 194 maybe supported with any well-known D2D RAT, such as LTE Direct (LTE-D),WiFi Direct (WiFi-D), Bluetooth®, and so on.

The wireless communications system 100 may further include a UE 164 thatmay communicate with a macro cell base station 102 over a communicationlink 120 and/or the mmW base station 180 over a mmW communication link184. For example, the macro cell base station 102 may support a PCelland one or more SCells for the UE 164 and the mmW base station 180 maysupport one or more SCells for the UE 164.

According to various aspects, FIG. 2A illustrates an example wirelessnetwork structure 200. For example, an NGC 210 (also referred to as a“5GC”) can be viewed functionally as control plane functions 214 (e.g.,UE registration, authentication, network access, gateway selection,etc.) and user plane functions 212, (e.g., UE gateway function, accessto data networks, IP routing, etc.) which operate cooperatively to formthe core network. User plane interface (NG-U) 213 and control planeinterface (NG-C) 215 connect the gNB 222 to the NGC 210 and specificallyto the control plane functions 214 and user plane functions 212. In anadditional configuration, an eNB 224 may also be connected to the NGC210 via NG-C 215 to the control plane functions 214 and NG-U 213 to userplane functions 212. Further, eNB 224 may directly communicate with gNB222 via a backhaul connection 223. In some configurations, the New RAN220 may only have one or more gNBs 222, while other configurationsinclude one or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB224 may communicate with UEs 204 (e.g., any of the UEs depicted in FIG.1). Another optional aspect may include location server 230 (which maycorrespond to location server 172), which may be in communication withthe NGC 210 to provide location assistance for UEs 204. The locationserver 230 can be implemented as a plurality of separate servers (e.g.,physically separate servers, different software modules on a singleserver, different software modules spread across multiple physicalservers, etc.), or alternately may each correspond to a single server.The location server 230 can be configured to support one or morelocation services for UEs 204 that can connect to the location server230 via the core network, NGC 210, and/or via the Internet (notillustrated). Further, the location server 230 may be integrated into acomponent of the core network, or alternatively may be external to thecore network.

According to various aspects, FIG. 2B illustrates another examplewireless network structure 250. For example, an NGC 260 (also referredto as a “5GC”) can be viewed functionally as control plane functions,provided by an access and mobility management function (AMF)/user planefunction (UPF) 264, and user plane functions, provided by a sessionmanagement function (SMF) 262, which operate cooperatively to form thecore network (i.e., NGC 260). User plane interface 263 and control planeinterface 265 connect the eNB 224 to the NGC 260 and specifically to SMF262 and AMF/UPF 264, respectively. In an additional configuration, a gNB222 may also be connected to the NGC 260 via control plane interface 265to AMF/UPF 264 and user plane interface 263 to SMF 262. Further, eNB 224may directly communicate with gNB 222 via the backhaul connection 223,with or without gNB direct connectivity to the NGC 260. In someconfigurations, the New RAN 220 may only have one or more gNBs 222,while other configurations include one or more of both eNBs 224 and gNBs222. Either gNB 222 or eNB 224 may communicate with UEs 204 (e.g., anyof the UEs depicted in FIG. 1). The base stations of the New RAN 220communicate with the AMF-side of the AMF/UPF 264 over the N2 interfaceand the UPF-side of the AMF/UPF 264 over the N3 interface.

The functions of the AMF include registration management, connectionmanagement, reachability management, mobility management, lawfulinterception, transport for session management (SM) messages between theUE 204 and the SMF 262, transparent proxy services for routing SMmessages, access authentication and access authorization, transport forshort message service (SMS) messages between the UE 204 and the shortmessage service function (SMSF) (not shown), and security anchorfunctionality (SEAF). The AMF also interacts with the authenticationserver function (AUSF) (not shown) and the UE 204, and receives theintermediate key that was established as a result of the UE 204authentication process. In the case of authentication based on a UMTS(universal mobile telecommunications system) subscriber identity module(USIM), the AMF retrieves the security material from the AUSF. Thefunctions of the AMF also include security context management (SCM). TheSCM receives a key from the SEAF that it uses to derive access-networkspecific keys. The functionality of the AMF also includes locationservices management for regulatory services, transport for locationservices messages between the UE 204 and the location managementfunction (LMF) 270 (which may correspond to location server 172), aswell as between the New RAN 220 and the LMF 270, evolved packet system(EPS) bearer identifier allocation for interworking with the EPS, and UE204 mobility event notification. In addition, the AMF also supportsfunctionalities for non-Third Generation Partnership Project (3GPP)access networks.

Functions of the UPF include acting as an anchor point forintra-/inter-RAT mobility (when applicable), acting as an externalprotocol data unit (PDU) session point of interconnect to the datanetwork (not shown), providing packet routing and forwarding, packetinspection, user plane policy rule enforcement (e.g., gating,redirection, traffic steering), lawful interception (user planecollection), traffic usage reporting, quality of service (QoS) handlingfor the user plane (e.g., UL/DL rate enforcement, reflective QoS markingin the DL), UL traffic verification (service data flow (SDF) to QoS flowmapping), transport level packet marking in the UL and DL, DL packetbuffering and DL data notification triggering, and sending andforwarding of one or more “end markers” to the source RAN node.

The functions of the SMF 262 include session management, UE Internetprotocol (IP) address allocation and management, selection and controlof user plane functions, configuration of traffic steering at the UPF toroute traffic to the proper destination, control of part of policyenforcement and QoS, and downlink data notification. The interface overwhich the SMF 262 communicates with the AMF-side of the AMF/UPF 264 isreferred to as the N11 interface.

Another optional aspect may include a LMF 270, which may be incommunication with the NGC 260 to provide location assistance for UEs204. The LMF 270 can be implemented as a plurality of separate servers(e.g., physically separate servers, different software modules on asingle server, different software modules spread across multiplephysical servers, etc.), or alternately may each correspond to a singleserver. The LMF 270 can be configured to support one or more locationservices for UEs 204 that can connect to the LMF 270 via the corenetwork, NGC 260, and/or via the Internet (not illustrated).

According to various aspects, FIG. 3 illustrates an exemplary basestation 302 (e.g., an eNB, a gNB, a small cell AP, a WLAN AP, etc.) incommunication with an exemplary UE 304 in a wireless network, accordingto aspects of the disclosure. The base station 302 may correspond to anyof the base stations described herein. In the DL, IP packets from thecore network (NGC 210/EPC 260) may be provided to a controller/processor375. The controller/processor 375 implements functionality for a radioresource control (RRC) layer, a packet data convergence protocol (PDCP)layer, a radio link control (RLC) layer, and a medium access control(MAC) layer. The controller/processor 375 provides RRC layerfunctionality associated with broadcasting of system information (e.g.,MIB, SIBs), RRC connection control (e.g., RRC connection paging, RRCconnection establishment, RRC connection modification, and RRCconnection release), inter-RAT mobility, and measurement configurationfor UE measurement reporting; PDCP layer functionality associated withheader compression/decompression, security (ciphering, deciphering,integrity protection, integrity verification), and handover supportfunctions; RLC layer functionality associated with the transfer of upperlayer packet data units (PDUs), error correction through automaticrepeat request (ARQ), concatenation, segmentation, and reassembly of RLCservice data units (SDUs), re-segmentation of RLC data PDUs, andreordering of RLC data PDUs; and MAC layer functionality associated withmapping between logical channels and transport channels, schedulinginformation reporting, error correction, priority handling, and logicalchannel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370implement Layer-1 functionality associated with various signalprocessing functions. Layer-1, which includes a physical (PHY) layer,may include error detection on the transport channels, forward errorcorrection (FEC) coding/decoding of the transport channels,interleaving, rate matching, mapping onto physical channels,modulation/demodulation of physical channels, and MIMO antennaprocessing. The TX processor 316 handles mapping to signalconstellations based on various modulation schemes (e.g., binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an OFDM subcarrier,multiplexed with a reference RF signal (e.g., pilot) in the time and/orfrequency domain, and then combined together using an Inverse FastFourier Transform (IFFT) to produce a physical channel carrying a timedomain OFDM symbol stream. The OFDM stream is spatially precoded toproduce multiple spatial streams. Channel estimates from a channelestimator 374 may be used to determine the coding and modulation scheme,as well as for spatial processing. The channel estimate may be derivedfrom a reference RF signal and/or channel condition feedback transmittedby the UE 304. Each spatial stream may then be provided to one or moredifferent antennas 320 via a separate transmitter 318 a. Eachtransmitter 318 a may modulate an RF carrier with a respective spatialstream for transmission.

At the UE 304 (which may correspond to any of the UEs described herein),each receiver 354 a receives a signal through its respective antenna352. Each receiver 354 a recovers information modulated onto an RFcarrier and provides the information to the RX processor 356. The TXprocessor 368 and the RX processor 356 implement Layer-1 functionalityassociated with various signal processing functions. The RX processor356 may perform spatial processing on the information to recover anyspatial streams destined for the UE 304. If multiple spatial streams aredestined for the UE 304, they may be combined by the RX processor 356into a single OFDM symbol stream. The RX processor 356 then converts theOFDM symbol stream from the time-domain to the frequency domain using afast Fourier transform (FFT). The frequency domain signal comprises aseparate OFDM symbol stream for each subcarrier of the OFDM signal. Thesymbols on each subcarrier, and the reference RF signal, are recoveredand demodulated by determining the most likely signal constellationpoints transmitted by the base station 302. These soft decisions may bebased on channel estimates computed by the channel estimator 358. Thesoft decisions are then decoded and de-interleaved to recover the dataand control signals that were originally transmitted by the base station302 on the physical channel. The data and control signals are thenprovided to the controller/processor 359, which implements Layer-3 andLayer-2 functionality.

The controller/processor 359 can be associated with a memory 360 thatstores program codes and data. The memory 360 may be referred to as acomputer-readable medium. In the UL, the controller/processor 359provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing to recover IP packets from the core network. Thecontroller/processor 359 is also responsible for error detection.

Similar to the functionality described in connection with the DLtransmission by the base station 302, the controller/processor 359provides RRC layer functionality associated with system information(e.g., MIB, SIBs) acquisition, RRC connections, and measurementreporting; PDCP layer functionality associated with headercompression/decompression, and security (ciphering, deciphering,integrity protection, integrity verification); RLC layer functionalityassociated with the transfer of upper layer PDUs, error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC SDUs,re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto transport blocks(TBs), demultiplexing of MAC SDUs from TBs, scheduling informationreporting, error correction through hybrid automatic repeat request(HARM), priority handling, and logical channel prioritization.

Channel estimates derived by the channel estimator 358 from a referenceRF signal or feedback transmitted by the base station 302 may be used bythe TX processor 368 to select the appropriate coding and modulationschemes, and to facilitate spatial processing. The spatial streamsgenerated by the TX processor 368 may be provided to different antenna352 via separate transmitters 354 b. Each transmitter 354 b may modulatean RF carrier with a respective spatial stream for transmission. In anaspect, the transmitters 354 b and the receivers 354 a may be one ormore transceivers, one or more discrete transmitters, one or morediscrete receivers, or any combination thereof.

The UL transmission is processed at the base station 302 in a mannersimilar to that described in connection with the receiver function atthe UE 304. Each receiver 318 b receives a signal through its respectiveantenna 320. Each receiver 318 b recovers information modulated onto anRF carrier and provides the information to a RX processor 370. In anaspect, the transmitters 318 a and the receivers 318 b may be one ormore transceivers, one or more discrete transmitters, one or morediscrete receivers, or any combination thereof.

The controller/processor 375 can be associated with a memory 376 thatstores program codes and data. The memory 376 may be referred to as acomputer-readable medium. In the UL, the controller/processor 375provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover IP packets from the UE 304. IP packets from thecontroller/processor 375 may be provided to the core network. Thecontroller/processor 375 is also responsible for error detection.

FIG. 4 illustrates an exemplary wireless communications system 400according to various aspects of the disclosure. In the example of FIG.4, a UE 404, which may correspond to any of the UEs described herein, isattempting to calculate an estimate of its position, or assist anotherentity (e.g., a base station or core network component, another UE, alocation server, a third party application, etc.) to calculate anestimate of its position. The UE 404 may communicate wirelessly with aplurality of base stations 402-1, 402-2, and 402-3 (collectively, basestations 402), which may correspond to any combination of the basestations described herein, using RF signals and standardized protocolsfor the modulation of the RF signals and the exchange of informationpackets. By extracting different types of information from the exchangedRF signals, and utilizing the layout of the wireless communicationssystem 400 (e.g., the base stations' locations, geometry, etc.), the UE404 may determine its position, or assist in the determination of itsposition, in a predefined reference coordinate system. In an aspect, theUE 404 may specify its position using a two-dimensional (2D) coordinatesystem; however, the aspects disclosed herein are not so limited, andmay also be applicable to determining positions using athree-dimensional (3D) coordinate system, if the extra dimension isdesired. Additionally, while FIG. 4 illustrates one UE 404 and four basestations 402, as will be appreciated, there may be more UEs 404 and moreor fewer base stations 402.

To support position estimates, the base stations 402 may be configuredto broadcast reference RF signals (e.g., PRS, NRS, transmitter referencesignals (TRS), cell-specific reference signals (CRS), channel stateinformation reference signals (CSI-RS), primary synchronization signals(PSS), secondary synchronization signals (SSS), etc.) to UEs 404 intheir coverage area to enable a UE 404 to measure characteristics ofsuch reference RF signals. For example, the observed time difference ofarrival (OTDOA) positioning method, defined by 3GPP (e.g., in 3GPPTechnical Specification (TS) 36.355) for wireless networks that providewireless access using 5G NR, is a multilateration method in which the UE404 measures the time difference, known as an RSTD, between specificreference RF signals (e.g., PRS, CRS, CSI-RS, etc.) transmitted bydifferent pairs of network nodes (e.g., base stations 402, antennas ofbase stations 402, etc.) and either reports these time differences to alocation server, such as the location server 230 or LMF 270, or computesa location estimate itself from these time differences.

The term “position estimate” is used herein to refer to an estimate of aposition for a UE, which may be geographic (e.g., may comprise alatitude, longitude, and possibly altitude) or civic (e.g., may comprisea street address, building designation, or precise point or area withinor nearby to a building or street address, such as a particular entranceto a building, a particular room or suite in a building, or a landmarksuch as a town square). A position estimate may also be referred to as a“location,” a “position,” a “fix,” a “position fix,” a “location fix,” a“location estimate,” a “fix estimate,” or by some other term. The meansof obtaining a location estimate may be referred to generically as“positioning,” “locating,” or “position fixing.” A particular solutionfor obtaining a position estimate may be referred to as a “positionsolution.” A particular method for obtaining a position estimate as partof a position solution may be referred to as, for example, a “positionmethod” or as a “positioning method.” A position estimate may include anexpected error or uncertainty (e.g., by including an area or volumewithin which the location is expected to be included with some specifiedor default level of confidence).

Generally, RSTDs are measured between a reference network node (e.g.,base station 402-1 in the example of FIG. 4) and one or more neighbornetwork nodes (e.g., base stations 402-2 and 402-3 in the example ofFIG. 4). The reference network node remains the same for all RSTDsmeasured by the UE 404 for any single positioning use of OTDOA and wouldtypically correspond to the serving cell for the UE 404 or anothernearby cell with good signal strength at the UE 404. In an aspect, wherea measured network node is a cell supported by a base station, theneighbor network nodes would normally be cells supported by basestations different from the base station for the reference cell and mayhave good or poor signal strength at the UE 404. The locationcomputation can be based on the measured time differences (e.g., RSTDs)and knowledge of the network nodes' locations and relative transmissiontiming (e.g., regarding whether network nodes are accuratelysynchronized or whether each network node transmits with some known timedifference relative to other network nodes).

To assist positioning operations, a location server (e.g., locationserver 230, LMF 270) may provide OTDOA assistance data to the UE 404 forthe reference network node (e.g., base station 402-1 in the example ofFIG. 4) and the neighbor network nodes (e.g., base stations 402-2 and402-3 in the example of FIG. 4) relative to the reference network node.For example, the assistance data may provide the center channelfrequency of each network node, various reference RF signalconfiguration parameters (e.g., the number of consecutive positioningsubframes, periodicity of positioning subframes, muting sequence,frequency hopping sequence, reference RF signal identifier (ID),reference RF signal bandwidth), a network node global ID, and/or othercell related parameters applicable to OTDOA. The OTDOA assistance datamay indicate the serving cell for the UE 404 as the reference networknode.

In some cases, OTDOA assistance data may also include “expected RSTD”parameters, which provide the UE 104 with information about the RSTDvalues the UE 404 is expected to measure at its current location betweenthe reference network node and each neighbor network node, together withan uncertainty of the expected RSTD parameter. The expected RSTD,together with the associated uncertainty, may define a search window forthe UE 404 within which the UE 404 is expected to measure the RSTDvalue. OTDOA assistance information may also include reference RF signalconfiguration information parameters, which allow a UE 404 to determinewhen a reference RF signal positioning occasion occurs on signalsreceived from various neighbor network nodes relative to reference RFsignal positioning occasions for the reference network node, and todetermine the reference RF signal sequence transmitted from variousnetwork nodes in order to measure a signal time of arrival (ToA) orRSTD.

In an aspect, while the location server (e.g., location server 230, LMF270) may send the assistance data to the UE 404, alternatively, theassistance data can originate directly from the network nodes (e.g.,base stations 402) themselves (e.g., in periodically broadcastedoverhead messages, etc.). Alternatively, the UE 404 can detect neighbornetwork nodes itself without the use of assistance data.

The UE 404 (e.g., based in part on the assistance data, if provided) canmeasure and (optionally) report the RSTDs between reference RF signalsreceived from pairs of network nodes. Using the RSTD measurements, theknown absolute or relative transmission timing of each network node, andthe known position(s) of the transmitting antennas for the reference andneighboring network nodes, the network (e.g., location server 230/LMF270, a base station 402) or the UE 404 may estimate a position of the UE404. More particularly, the RSTD for a neighbor network node “k”relative to a reference network node “Ref” may be given as(ToA_(k)−ToA_(Ref)), where the ToA values may be measured modulo onesubframe duration (1 ms) to remove the effects of measuring differentsubframes at different times. In the example of FIG. 4, the measuredtime differences between the reference cell of base station 402-1 andthe cells of neighboring base stations 402-2 and 402-3 are representedas τ₂−τ₁ and τ₃−τ₁, where τ₁, τ₂, and τ₃ represent the ToA of areference RF signal from the transmitting antenna(s) of base station402-1, 402-2, and 402-3, respectively. The UE 440 may then convert theToA measurements for different network nodes to RSTD measurements (e.g.,as defined in 3GPP TS 36.214 entitled “Physical layer; Measurements”)and (optionally) send them to the location server 230/LMF 270. Using (i)the RSTD measurements, (ii) the known absolute or relative transmissiontiming of each network node, (iii) the known position(s) of physicaltransmitting antennas for the reference and neighboring network nodes,and/or (iv) directional reference RF signal characteristics such as adirection of transmission, the UE's 404 position may be determined(either by the UE 404 or the location server 230/LMF 270).

Still referring to FIG. 4, when the UE 404 obtains a location estimateusing OTDOA measured time differences, the necessary additional data(e.g., the network nodes' locations and relative transmission timing)may be provided to the UE 404 by a location server (e.g., locationserver 230, LMF 270). In some implementations, a location estimate forthe UE 404 may be obtained (e.g., by the UE 404 itself or by thelocation server 230/LMF 270) from OTDOA measured time differences andfrom other measurements made by the UE 404 (e.g., measurements of signaltiming from global positioning system (GPS) or other global navigationsatellite system (GNSS) satellites). In these implementations, known ashybrid positioning, the OTDOA measurements may contribute towardsobtaining the UE's 404 location estimate but may not wholly determinethe location estimate.

Uplink time difference of arrival (UTDOA) is a similar positioningmethod to OTDOA, but is based on uplink reference RF signals (e.g.,sounding reference signals (SRS), uplink positioning reference signals(UL PRS)) transmitted by the UE (e.g., UE 304). Further, transmissionand/or reception beamforming at the base station 302 and/or UE 304 canenable wideband bandwidth at the cell edge for increased precision. Beamrefinements may also leverage channel reciprocity procedures in 5G NR.

As used herein, a “network node” may be a base station (e.g., a basestation 302), a cell of a base station (e.g., a cell of a base station302), an RRH, a DAS, an antenna of a base station (e.g., an antenna of abase station 302, where the locations of the antennas of a base stationare distinct from the location of the base station itself), an array ofantennas of a base station (e.g., an array of antennas of a base station302, where the locations of the antenna arrays are distinct from thelocation of the base station itself), or any other network entitycapable of transmitting reference RF signals. Further, as used herein, a“network node” may also refer to a UE other than the UE beingpositioned.

The term “base station” may refer to a single physical transmissionpoint or to multiple physical transmission points that may or may not beco-located. For example, where the term “base station” refers to asingle physical transmission point, the physical transmission point maybe an antenna of the base station (e.g., a base station 302)corresponding to a cell of the base station. Where the term “basestation” refers to multiple co-located physical transmission points, thephysical transmission points may be an array of antennas (e.g., as in amultiple input-multiple output (MIMO) system or where the base stationemploys beamforming) of the base station. Where the term “base station”refers to multiple non-co-located physical transmission points, thephysical transmission points may be a DAS (a network of spatiallyseparated antennas connected to a common source via a transport medium)or an RRH (a remote base station connected to a serving base station).Alternatively, the non-co-located physical transmission points may bethe serving base station receiving the measurement report from the UE(e.g., UE 304) and a neighbor base station whose reference RF signalsthe UE 304 is measuring.

In order to identify the ToA of a reference RF signal transmitted by agiven network node (e.g., base station 302), the UE (e.g., UE 304) firstjointly processes all the resource elements on the channel on which thatnetwork node is transmitting the reference RF signal, and performs aninverse Fourier transform to convert the received RF signals to the timedomain. The conversion of the received RF signals to the time domain isreferred to as an estimation of the channel energy response (CER). TheCER shows the peaks on the channel over time, and the earliest“significant” peak should therefore correspond to the ToA of thereference RF signal. Generally, a UE will use a noise-related qualitythreshold to filter out spurious local peaks, thereby presumablycorrectly identifying significant peaks on the channel. For example, aUE may chose a ToA estimate that is the earliest local maximum of theCER that is at least ‘X’ decibels (dB) higher than the median of the CERand a maximum ‘Y’ dB lower than the main peak on the channel. The UEdetermines the CER for each reference RF signal from each network nodein order to determine the ToA of each reference RF signal from thedifferent network nodes.

FIGS. 5A and 5B illustrate graphs 500A and 500B, respectively, ofexemplary CERs, according to aspects of the disclosure. The y-axis ofgraphs 500A and 500B represent the power of the received RF signals indB, and the x-axis represents time. In graph 500A, plot 502A shows theCER when the SINR (defined as the power of a certain RF signal ofinterest divided by the sum of the interference power from all the otherinterfering RF signals and the power of some background noise) or delayspread (the difference between the ToA of the earliest significant peakand the ToA of the latest peak) information is not taken into account,and plot 504A shows the CER when the SINR or delay spread information istaken into account. Likewise, in graph 500B, plot 502B shows the CERwhen the SINR or delay spread information is not taken into account, andplot 504B shows the CER when it is.

As shown on plot 502A, when the SINR or delay spread information is nottaken into account, the peak at 512A may be incorrectly identified as a“significant” peak, and therefore as incorrectly corresponding to theToA (approximately 300 nanoseconds (ns)) of the measured reference RFsignal. In contrast, as shown on plot 514A, when the SINR or delayspread information is taken into account, the peak at 514A is correctlyidentified as a “significant” peak, and therefore, as corresponding tothe correct ToA (approximately 1700 ns) of the measured reference RFsignal. Thus, as can be seen in FIGS. 5A and 5B, when the SINR and/ordelay spread are taken into account, it is much easier to identify anactual peak, versus the spurious peaks caused by background noise on thechannel. As such, knowledge of the delay spread and/or SINR couldprovide cleaner CERs, and therefore, potentially fewer first-peakmisdetections.

Certain network nodes (whether a base station or a UE), especially thosecapable of 5G NR communication, may use beamforming to send and receiveinformation over a wireless channel. Transmit beams may bequasi-collocated, meaning that they appear to the receiver as having thesame parameters, regardless of whether or not the transmitting antennasthemselves are physically collocated. In 5G NR, there are four types ofquasi-collocation (QCL) relations. A QCL relation of a given type meansthat certain parameters about a second reference RF signal on a secondtransmit beam can be derived from information about a source referenceRF signal on a source transmit beam. Specifically, if the sourcereference RF signal is QCL Type A, the receiver can use the sourcereference RF signal to estimate the Doppler shift, Doppler spread,average delay, and delay spread of a second reference RF signaltransmitted on the same channel. If the source reference RF signal isQCL Type B, the receiver can use the source reference RF signal toestimate the Doppler shift and Doppler spread of a second reference RFsignal transmitted on the same channel. If the source reference RFsignal is QCL Type C, the receiver can use the source reference RFsignal to estimate the Doppler shift and average delay of a secondreference RF signal transmitted on the same channel. If the sourcereference RF signal is QCL Type D, the receiver can use the sourcereference RF signal to estimate the spatial receive parameter of asecond reference RF signal transmitted on the same channel.

FIG. 6 shows a graph 600 comparing a cumulative distribution function(CDF) to the distance error in meters for all initializations across allUEs of a particular sample set, according to aspects of the disclosure.Plot 602 illustrates the results of a comb-1 PRS pattern,transmit/receive beam pairing (i.e., both transmitter and receiver usebeamforming), and 13 dB noise figure (NF). Plot 604 illustrates theresults of a comb-4 PRS pattern, transmit/receive beam pairing, and 13dB NF. In the example of FIG. 6, the comb-4 pattern has an energy perresource element (EPRE) ratio of 6 dB. As can be seen in FIG. 6, theperformance loss appears in the tail of the CDF, after approximately the60% percentile.

If there are gaps in the frequency domain, such as with a comb-4 pattern(where reference RF signals are transmitted in the same OFDM symbolevery fourth subcarrier), it results in aliasing of the CER, especiallywhere the measured network node is far away. Aliasing is a result ofconverting the frequency domain to the time domain when estimating theCER, and appears as multiple equally-sized peaks, as shown in FIG. 7.FIG. 7 shows a graph 700 of a CER estimate where the detected referenceRF signal is transmitted using a comb-4 pattern, according to aspects ofthe disclosure. As shown in FIG. 7, the CER has four significant peaks,due to the fact that the reference RF signal is being transmitted with acomb-4 pattern and the UE (e.g., UE 304) is far away from the networknode. However, the UE may be unaware of this issue, and only one ofthese peaks is useful. Thus, in the example of FIG. 7, the UE detects asignificant peak at 702 and falsely identifies it as the strongestdetected peak. In reality, the true peak is at 704. This is an issuewith the frequency domain subsampling from using comb-4, especiallywhere the UE is far from the network node. For reference, the CER graphsin FIGS. 5A and 5B show the CER for a comb-1 pattern.

As such, it would be beneficial for a UE that has detected aliasing inthe CER to be able to identify which is the true peak for the channel.Accordingly, the present disclosure proposes a new QCL type thatconfigures a QCL source reference RF signal for the “average delay” (theaverage of the time the first channel tap of a multipath RF signal isreceived and the time the last channel tap of the multipath RF signal isreceived) or the “delay spread” (the time from when the first channeltap of a multipath RF signal is received to the time when the lastchannel tap of the multipath RF signal is received) or both, to enablethe UE (e.g., UE 304) to derive these values for a subsequentlytransmitted reference RF signal. If another reference RF signal isreceived as a QCL source for the “average delay” and/or “delay spread”for other reference RF signals on the channel, then the UE can estimatea crude CER from the source reference RF signal, determine a validwindow of where to look in the CER for the main peak of a reference RFsignal received on the channel, receive a subsequent reference RFsignal, and search for the ToA inside the determined window. As would beappreciated, the actual transmission parameters allowable for areference RF signal having QCL parameters for “average delay” and/or“delay spread” provided can be different than those if the QCL source isnot given.

FIG. 8A shows a graph 800A of an exemplary CER for a received referenceRF signal, according to aspects of the disclosure. In the example ofFIG. 8A, the UE (e.g., UE 304) has received a source reference RF signal(e.g., a TRS) configured for average delay only. As such, the UE willknow the average delay of subsequent reference RF signals received onthis channel from this network node (e.g., base station 302). Theaverage delay is represented as line 804. For a subsequently receivedreference RF signal (e.g., a PRS), the UE can listen some time thresholdbefore and after this delay average to detect any significant peaksoccurring within that threshold, and any significant peak detected(here, peak 802) can be considered the true peak for the reference RFsignal.

FIG. 8B shows a graph 800B of an exemplary CER for a received referenceRF signal, according to aspects of the disclosure. In the example ofFIG. 8B, the UE (e.g., UE 304) has received a source reference RF signal(e.g., a TRS) configured for average delay and delay spread. As such,the UE will know the average delay and delay spread of subsequentreference RF signals received on this channel from this network node(e.g., base station 302). The average delay and delay spread can be usedto determine window 806. The width of window 806 is the delay spreaddetermined from the source reference RF signal, and the center of thewindow 806 is set at the average delay determined from the sourcereference RF signal. For a subsequently received reference RF signal(e.g., a PRS), the UE can search within window 806 to detect anysignificant peaks occurring within the window 806, and any significantpeak detected (here, peak 802) can be considered the true peak for thereference RF signal. Note that multipath peaks may appear to the UE asbeing aliased. As such, it is preferable, when possible, to have boththe average delay and delay spread.

The present disclosure proposes to define new QCL relations, and use thesynchronization signal block (SSB) as the source reference RF signal forthese new QCL relations. For convenience, these new QCL types arereferred to as QCL Type E1, E2, and E. For a QCL Type E1, the UE can usethe source reference RF signal (an SSB) to estimate the average delay ofa second reference RF signal transmitted on the same channel. For a QCLType E2, the UE can use the source reference RF signal (an SSB) toestimate the delay spread of a second reference RF signal transmitted onthe same channel. For a QCL Type E, the UE can use the source referenceRF signal (an SSB) to estimate the average delay and delay spread of asecond reference RF signal transmitted on the same channel. The QCL type(E1/E2/E) could be a field in the SSB, and based on the QCL typecontained in the SSB, the UE would know which measurements it could takeof the SSB (delay spread, average delay, both).

Thus, reference RF signals transmitted on a given channel may beconfigured to have QCL Type E1, Type E2, or both (Type E), and thisconfiguration may be conveyed in another downlink reference RF signal,such as an SSB for the network node. Currently in 5G NR, QCL Type C orType C/D is allowed when the SSB is the source reference RF signal. Thedisclosure would add Type E. Alternatively, a statement could be addedto the applicable standard that when a reference RF signal is configuredfor QCL Type D, it is implicitly assumed that QCL Type E1 or E2 or bothtrue also. This allows a UE to receive an SSB from the network node andmake a crude estimate of the average delay and/or delay spread forreference RF signals from that network node depending on the QCL typeprovided (E1/E2/E), and then receive a subsequent reference RF signaland search for the early peak inside that smaller window.

A network node (e.g., base station 302) may use different sets ofreference RF signal transmission parameters if a QCL Type E sourcereference RF signal is provided. For example, QCL Type E (or E1 or E2)would allow a higher comb-type to be used for PRS; otherwise, afull-comb PRS (e.g., comb-1) should be used. This is because if a highercomb-level is used, aliasing is more likely to occur. However, if thePRS is configured with a source reference RF signal (e.g., an SSB) ofQCL Type E1/E2/E, then the UE can prune out the aliased CER and look forthe earliest peak inside the determined window, as discussed above withreference to FIGS. 8A and 8B. Further, if a QCL Type E source referenceRF signal is provided, the comb can be even higher than when only a QCLType E1 source reference RF signal is provided. For example, for a QCLType E1 source, a PRS with comb-2 could be transmitted, but for a QCLType E source, a PRS with comb-12 could be transmitted.

A network node may use different sets of reference RF signaltransmission parameters if a QCL Type E2 (delay spread) source referenceRF signal (e.g., an SSB) is provided but not a QCL Type E1 (averagedelay) source. For example, when a QCL Type E2 source reference RFsignal is provided for subsequent reference RF signals (e.g., PRS), thenthe subsequent reference RF signals from different cells can be allowedto be orthogonally code-division multiplexed (i.e., cyclic-shifted) witha configured cyclic shift. A cyclic shift changes the “average delay” ofthe channel, so in this case, the subsequent reference RF signals'“average delay” can be assumed to be the “average delay” of the sourcereference RF signal plus the cyclic shift. This is illustrated in FIG.9.

In FIG. 9, as shown in graph 910, the UE detects a cluster of channeltaps 912 for the SSB (“SSB1”) of a first cell (“cell 1”), and a clusterof channel taps 914 for the SSB (“SSB2”) of a second cell (“cell 2”).Although the UE detects the SSB1 before SSB2, it knows that these SSBshave been cycle shifted, and the amount of the cycle shift. As such, theUE can add the cyclic shift to the average delay, resulting in graph920, which accurately represents the order in which the SSBs would havebeen received without the cyclic shift.

As another example, the UE may be configured with ‘N’ PRS resources (aPRS resource is a collection of resource elements that are used fortransmission of PRS and may correspond to a beam or a cell of thenetwork node) from ‘N’ cells, each one with a different cyclic shift, onthe same OFDM symbol. Each PRS resource may be configured with a QCLType E2 by a corresponding SSB. The UE, by measuring the SSB, candetermine an appropriate window for each cell, which can then be shiftedaccording to the configured cyclic shift.

As yet another example, if a QCL Type E2 source reference RF signal(e.g., an SSB) is provided for all PRS resources transmitted on the sameOFDM symbol, then a higher number of cyclic shifts can be configured tothe UE compared to the case where the QCL Type E2 source is notprovided.

As yet another example, if a QCL Type E2 source reference RF signal(e.g., an SSB) is provided and cyclic shifts are used for network node(e.g., base station 302) orthogonalization, then a Zadoff-Chu sequencecan be used as a PRS sequence.

Note that although the foregoing has generally been described in termsof a network node, such as a base station, transmitting downlinkreference RF signals and the QCL type to a UE, as will be appreciated, aUE could transmit uplink reference RF signals and the QCL type to thenetwork node, and different network nodes, whether base stations or UEs,could transmit reference RF signals and the QCL type to each other.

FIG. 10 illustrates an exemplary method 1000 for receiving reference RFsignals for positioning estimation, according to aspects of thedisclosure. The method 1000 may be performed by a receiver device (e.g.,UE 304 on the downlink or base station 302 on the uplink).

At 1002, the receiver device (e.g., receiver 354 a and/or RX processor356, or receiver 318 b and/or RX processor 370) receives, from atransmission point (e.g., UE 304 on the uplink or base station 302 onthe downlink, an antenna or antenna array of base station 302, an RRH, aDAS, etc.), a reference RF signal (e.g., an SSB) on a wireless channel(e.g., communication link 120). In an aspect, the reference RF signalcomprises an SSB.

At 1004, the receiver device (e.g., receiver 354 a and/or RX processor356, or receiver 318 b and/or RX processor 370) receives, from apositioning entity (e.g., location server 230 or LMF 270), an indicationthat the reference RF signal serves as a source for a QCL type(s) (e.g.,E1/E2/E) for positioning reference RF signals received by the receiverdevice from the transmission point on the wireless channel.

At 1006, the receiver device (e.g., channel estimator 358 and/or RXprocessor 356, or channel estimator 374 and/or RX processor 370)measures an average delay, a delay spread, or both the average delay andthe delay spread of the source reference RF signal based on the QCLtype(s). In an aspect, the average delay comprises an average of a firsttime at which a first channel tap of the reference RF signal is receivedand a second time at which a last channel tap of the reference RF signalis received. In an aspect, the delay spread comprises an amount of timefrom a first time at which a first channel tap of the reference RFsignal is received to a second time at which a last channel tap of thereference RF signal is received.

At 1008, the receiver device (e.g., receiver 354 a and/or RX processor356, or receiver 318 b and/or RX processor 370) receives, from thetransmission point, a positioning reference RF signal (e.g., PRS, NRS,TRS, CRS, CSI-RS, etc.) on the wireless channel.

At 1010, the receiver device (e.g., channel estimator 358 and/or RXprocessor 356, or channel estimator 374 and/or RX processor 370)identifies a ToA of the positioning reference RF signal based on themeasured average delay, the delay spread, or both the average delay andthe delay spread of the reference RF signal.

In an aspect, the method 1000 may further include (not shown)calculating a CER for the positioning reference RF signal, andidentifying the ToA of the positioning reference RF signal based on apeak in the CER for the positioning reference RF signal occurring withina time period (window) defined by the average delay, the delay spread,or both the average delay and the delay spread.

In an aspect, the receiver device may be configured with a plurality ofpositioning reference RF signal resources from a plurality of cells,wherein each positioning reference RF signal resource is carried on thesame OFDM symbol and has a different cyclic shift. In this case, themethod 1000 further includes (not shown) measuring, for each positioningreference RF signal resource, a delay spread of a reference RF signaltransmitted on the positioning reference RF signal resource,determining, for each cell, a time period defined by the delay spread ofthe reference RF signal transmitted on the positioning reference RFsignal resource of that cell, and shifting, for each cell, the timeperiod based on the cyclic shift of the positioning reference RF signalresource of that cell. The method 1000 may further include (not shown)receiving, from the transmission point, a positioning reference RFsignal on each of the plurality of positioning reference RF signalresources, wherein a sequence used for each positioning reference RFsignal is a Zadoff-Chu sequence, and wherein each cell shifts theZadoff-Chu sequence with the respective cycle shift.

In an aspect, the method 1000 further includes (not shown) receiving, atthe receiver device from a second transmission point, a second referenceRF signal on a second wireless channel, receiving, at the receiverdevice from the transmission point, an indication that the secondreference RF signal serves as a source for a second QCL type(s) forpositioning reference RF signals received by the receiver device fromthe second transmission point on the second wireless channel, measuring,by the receiver device, a second average delay, a second delay spread,or both the second average delay and the second delay spread of thesecond reference RF signal based on the second QCL type(s), receiving,at the receiver device from the second transmission point, a secondpositioning reference RF signal on the second wireless channel, andidentifying, by the receiver device, a second ToA of the secondpositioning reference RF signal based on the second average delay, thesecond delay spread, or both the second average delay and the seconddelay spread of the second reference RF signal. In an aspect, the method1000 may further include (not shown) performing a positioning operationbased on the ToA of the positioning reference RF signal and the secondToA of the second positioning reference RF signal, wherein thepositioning operation comprises a calculation of a RSTD between the ToAand the second ToA. In an aspect, the receiver device reports the RSTDto the positioning entity.

In an aspect, the QCL type(s) indicates that the reference RF signal andthe positioning reference RF signal have the same average delay only,the same delay spread only, or both the same average delay and the samedelay spread. In an aspect, based on the QCL type(s) indicating that thereference RF signal and the positioning reference RF signal have boththe same average delay and the same delay spread, the transmission pointuses a higher comb-type to transmit the positioning reference RF signalthan where the QCL type(s) indicates that the reference RF signal andthe positioning reference RF signal have the same average delay only orthe same delay spread only. In an aspect, the transmission point uses ahigher comb-type to transmit the positioning reference RF signal thancould be used if the QCL type(s) did not indicate that the reference RFsignal and the positioning reference RF signal have the same averagedelay only, the same delay spread only, or both the same average delayand the same delay spread.

FIG. 11 illustrates an exemplary method 1100 for transmitting referenceRF signals for positioning estimation, according to aspects of thedisclosure. The method 1100 may be performed by a transmission point(e.g., UE 304 on the uplink, an antenna or antenna array of UE 304, basestation 302 on the downlink, an antenna or antenna array of base station302, etc.).

At 1102, the transmission point (e.g., transmitter 318 a and/or TXprocessor 316, or transmitter 354 b and/or TX processor 368) transmits,to a receiver device (e.g., UE 304 on the downlink or base station 302on the uplink), a reference RF signal on a wireless channel.

At 1104, the transmission point (e.g., transmitter 318 a and/or TXprocessor 316, or transmitter 354 b and/or TX processor 368) transmits,to the receiver device, an indication that the reference RF signalserves as a source for a QCL type(s) for positioning reference RFsignals received by the receiver device from the transmission point onthe wireless channel.

At 1102, the transmission point (e.g., transmitter 318 a and/or TXprocessor 316, or transmitter 354 b and/or TX processor 368) transmits,to the receiver device, a positioning reference RF signal on thewireless channel according to the QCL type(s), wherein the QCL type(s)indicates that the reference RF signal and the positioning reference RFsignal have the same average delay only, the same delay spread only, orboth the same average delay and the same delay spread.

In an aspect, the method 1100 further includes (not shown) receiving,from the receiver device, a ToA of the positioning reference RF signalcalculated based on a measured average delay, a measured delay spread,or both the measured average delay and the measured delay spread of thereference RF signal.

In an aspect, based on the QCL type(s) indicating that the reference RFsignal and the positioning reference RF signals have both the sameaverage delay and the same delay spread, the transmission point uses ahigher comb-type to transmit the positioning reference RF signal thanwhere the QCL type(s) indicates that the reference RF signal and thepositioning reference RF signal have the same average delay only or thesame delay spread only.

In an aspect, the transmission point uses a higher comb-type to transmitthe positioning reference RF signal than could be used if the QCLtype(s) did not indicate that the reference RF signal and thepositioning reference RF signal have the same average delay only, thesame delay spread only, or both the same average delay and the samedelay spread.

Those skilled in the art will appreciate that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Further, those skilled in the art will appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the aspects disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted to departfrom the scope of the various aspects described herein.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an ASIC, a field programmable gate array (FPGA) or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices(e.g., a combination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or other such configurations).

The methods, sequences, and/or algorithms described in connection withthe aspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in random access memory (RAM), flashmemory, read-only memory (ROM), erasable programmable ROM (EPROM),electrically erasable programmable ROM (EEPROM), registers, hard disk, aremovable disk, a CD-ROM, or any other form of non-transitorycomputer-readable medium known in the art. An exemplary non-transitorycomputer-readable medium may be coupled to the processor such that theprocessor can read information from, and write information to, thenon-transitory computer-readable medium. In the alternative, thenon-transitory computer-readable medium may be integral to theprocessor. The processor and the non-transitory computer-readable mediummay reside in an ASIC. The ASIC may reside in a user device (e.g., a UE)or a base station. In the alternative, the processor and thenon-transitory computer-readable medium may be discrete components in auser device or base station.

In one or more exemplary aspects, the functions described herein may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on a non-transitorycomputer-readable medium. Computer-readable media may include storagemedia and/or communication media including any non-transitory mediumthat may facilitate transferring a computer program from one place toanother. A storage media may be any available media that can be accessedby a computer. By way of example, and not limitation, suchcomputer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave, then the coaxial cable, fiber opticcable, twisted pair, DSL, or wireless technologies such as infrared,radio, and microwave are included in the definition of a medium. Theterm disk and disc, which may be used interchangeably herein, includes acompact disk (CD), laser disc, optical disk, digital video disk (DVD),floppy disk, and Blu-ray discs, which usually reproduce datamagnetically and/or optically with lasers. Combinations of the aboveshould also be included within the scope of computer-readable media.

While the foregoing disclosure shows illustrative aspects, those skilledin the art will appreciate that various changes and modifications couldbe made herein without departing from the scope of the disclosure asdefined by the appended claims. Furthermore, in accordance with thevarious illustrative aspects described herein, those skilled in the artwill appreciate that the functions, steps, and/or actions in any methodsdescribed above and/or recited in any method claims appended hereto neednot be performed in any particular order. Further still, to the extentthat any elements are described above or recited in the appended claimsin a singular form, those skilled in the art will appreciate thatsingular form(s) contemplate the plural as well unless limitation to thesingular form(s) is explicitly stated.

What is claimed is:
 1. A method of wireless communication performed by a receiver device, comprising: receiving, from a transmission point, a reference RF signal on a wireless channel; receiving, from a positioning entity, an indication that the reference RF signal serves as a source for a quasi-collocation (QCL) type(s) for positioning reference RF signals received by the receiver device from the transmission point on the wireless channel; measuring an average delay, a delay spread, or both the average delay and the delay spread of the reference RF signal based on the QCL type(s); receiving, from the transmission point, a positioning reference RF signal on the wireless channel; and identifying a time of arrival (ToA) of the positioning reference RF signal based on the measured average delay, the delay spread, or both the average delay and the delay spread of the reference RF signal.
 2. The method of claim 1, further comprising: calculating a channel energy response for the positioning reference RF signal; and identifying the ToA of the positioning reference RF signal based on a peak in the channel energy response for the positioning reference RF signal occurring within a time period defined by the average delay, the delay spread, or both the average delay and the delay spread.
 3. The method of claim 1, wherein the average delay comprises an average of a first time at which a first channel tap of the reference RF signal is received and a second time at which a last channel tap of the reference RF signal is received.
 4. The method of claim 1, wherein the delay spread comprises an amount of time from a first time at which a first channel tap of the reference RF signal is received to a second time at which a last channel tap of the reference RF signal is received.
 5. The method of claim 1, wherein the reference RF signal comprises a synchronization signal block (SSB).
 6. The method of claim 1, wherein the positioning reference RF signal comprises a positioning reference signal (PRS), a navigation reference signal (NRS), a transmitter reference signal (TRS), a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a primary synchronization signal (PSS), or a secondary synchronization signal (SSS).
 7. The method of claim 1, wherein the receiver device is configured with a plurality of positioning reference RF signal resources from a plurality of cells, wherein each positioning reference RF signal resource is carried on the same orthogonal frequency division multiplexing (OFDM) symbol and has a different cyclic shift, the method further comprising: measuring, for each positioning reference RF signal resource, a delay spread of a reference RF signal transmitted on the positioning reference RF signal resource; determining, for each cell, a time period defined by the delay spread of the reference RF signal transmitted on the positioning reference RF signal resource of that cell; and shifting, for each cell, the time period based on the cyclic shift of the positioning reference RF signal resource of that cell.
 8. The method of claim 7, the method further comprising: receiving, from the transmission point, a positioning reference RF signal on each of the plurality of positioning reference RF signal resources, wherein a sequence used for each positioning reference RF signal is a Zadoff-Chu sequence, and wherein each cell shifts the Zadoff-Chu sequence with the respective cycle shift.
 9. The method of claim 1, further comprising: receiving, at the receiver device from a second transmission point, a second reference RF signal on a second wireless channel; receiving, at the receiver device from the transmission point, an indication that the second reference RF signal serves as a source for a second QCL type(s) for positioning reference RF signals received by the receiver device from the second transmission point on the second wireless channel; measuring, by the receiver device, a second average delay, a second delay spread, or both the second average delay and the second delay spread of the second reference RF signal based on the second QCL type(s); receiving, at the receiver device from the second transmission point, a second positioning reference RF signal on the second wireless channel; and identifying, by the receiver device, a second ToA of the second positioning reference RF signal based on the second average delay, the second delay spread, or both the second average delay and the second delay spread of the second reference RF signal.
 10. The method of claim 9, further comprising: performing a positioning operation based on the ToA of the positioning reference RF signal and the second ToA of the second positioning reference RF signal, wherein the positioning operation comprises a calculation of a reference signal timing difference (RSTD) between the ToA and the second ToA.
 11. The method of claim 10, wherein the receiver device reports the RSTD to the positioning entity.
 12. The method of claim 1, wherein the QCL type(s) indicates that the reference RF signal and the positioning reference RF signal have the same average delay only, the same delay spread only, or both the same average delay and the same delay spread.
 13. The method of claim 12, wherein, based on the QCL type(s) indicating that the reference RF signal and the positioning reference RF signal have both the same average delay and the same delay spread, the transmission point uses a higher comb-type to transmit the positioning reference RF signal than where the QCL type(s) indicates that the reference RF signal and the positioning reference RF signal have the same average delay only or the same delay spread only.
 14. The method of claim 12, wherein the transmission point uses a higher comb-type to transmit the positioning reference RF signal than could be used if the QCL type(s) did not indicate that the reference RF signal and the positioning reference RF signal have the same average delay only, the same delay spread only, or both the same average delay and the same delay spread.
 15. The method of claim 1, wherein the receiver device comprises a user equipment (UE) and the transmission point comprises a base station.
 16. The method of claim 1, wherein the receiver device comprises a base station and the transmission point comprises a user equipment (UE).
 17. A method of wireless communication performed by a transmission point, comprising: transmitting, to a receiver device, a reference RF signal on a wireless channel; transmitting, to the receiver device, an indication that the reference RF signal serves as a source for a quasi-collocation (QCL) type(s) for positioning reference RF signals received by the receiver device from the transmission point on the wireless channel; and transmitting, to the receiver device, a positioning reference RF signal on the wireless channel according to the QCL type(s), wherein the QCL type(s) indicates that the reference RF signal and the positioning reference RF signal have the same average delay only, the same delay spread only, or both the same average delay and the same delay spread.
 18. The method of claim 17, further comprising: receiving, from the receiver device, a time of arrival (ToA) of the positioning reference RF signal calculated based on a measured average delay, a measured delay spread, or both the measured average delay and the measured delay spread of the reference RF signal.
 19. The method of claim 17, wherein, based on the QCL type(s) indicating that the reference RF signal and the positioning reference RF signals have both the same average delay and the same delay spread, the transmission point uses a higher comb-type to transmit the positioning reference RF signal than where the QCL type(s) indicates that the reference RF signal and the positioning reference RF signal have the same average delay only or the same delay spread only.
 20. The method of claim 17, wherein the transmission point uses a higher comb-type to transmit the positioning reference RF signal than could be used if the QCL type(s) did not indicate that the reference RF signal and the positioning reference RF signal have the same average delay only, the same delay spread only, or both the same average delay and the same delay spread.
 21. The method of claim 17, wherein the receiver device comprises a user equipment (UE) and the transmission point comprises a base station.
 22. The method of claim 17, wherein the receiver device comprises a base station and the transmission point comprises a user equipment (UE).
 23. An apparatus for wireless communication, comprising: at least one receiver of a receiver device configured to: receive, from a transmission point, a reference RF signal on a wireless channel; and receive, from the transmission point, an indication that the reference RF signal serves as a source for a quasi-collocation (QCL) type(s) for positioning reference RF signals received by the receiver device from the transmission point on the wireless channel; and at least one processor of the receiver device configured to: measure an average delay, a delay spread, or both the average delay and the delay spread of the source reference RF signal based on the QCL type(s), wherein the at least one receiver is further configured to receive, from the transmission point, a positioning reference RF signal on the wireless channel, and wherein the at least one processor is further configured to identify a time of arrival (ToA) of the positioning reference RF signal based on the measured average delay, the delay spread, or both the average delay and the delay spread of the reference RF signal.
 24. The apparatus of claim 23, wherein the at least one processor is further configured to: calculate a channel energy response for the positioning reference RF signal; and identify the ToA of the positioning reference RF signal based on a peak in the channel energy response for the positioning reference RF signal occurring within a time period defined by the average delay, the delay spread, or both the average delay and the delay spread.
 25. The apparatus of claim 23, wherein the QCL type(s) indicates that the reference RF signal and the positioning reference RF signal have the same average delay only, the same delay spread only, or both the same average delay and the same delay spread.
 26. The apparatus of claim 25, wherein, based on the QCL type(s) indicating that the reference RF signal and the positioning reference RF signal have both the same average delay and the same delay spread, the transmission point uses a higher comb-type to transmit the positioning reference RF signal than where the QCL type(s) indicates that the reference RF signal and the positioning reference RF signal have the same average delay only or the same delay spread only.
 27. The apparatus of claim 25, wherein the transmission point uses a higher comb-type to transmit the positioning reference RF signal than could be used if the QCL type(s) did not indicate that the reference RF signal and the positioning reference RF signal have the same average delay only, the same delay spread only, or both the same average delay and the same delay spread.
 28. An apparatus for wireless communication, comprising: a transmitter of a transmission point configured to: transmit, to a receiver device, a reference RF signal on a wireless channel; transmit, to the receiver device, an indication that the reference RF signal serves as a source for a quasi-collocation (QCL) type(s) for positioning reference RF signals received by the receiver device from the transmission point on the wireless channel; and transmit, to the receiver device, a positioning reference RF signal on the wireless channel according to the QCL type(s), wherein the QCL type(s) indicates that the reference RF signal and the positioning reference RF signal have the same average delay only, the same delay spread only, or both the same average delay and the same delay spread.
 29. The apparatus of claim 28, wherein, based on the QCL type(s) indicating that the reference RF signal and the positioning reference RF signals have both the same average delay and the same delay spread, the transmission point uses a higher comb-type to transmit the positioning reference RF signal than where the QCL type(s) indicates that the reference RF signal and the positioning reference RF signal have the same average delay only or the same delay spread only.
 30. The apparatus of claim 28, wherein the transmission point uses a higher comb-type to transmit the positioning reference RF signal than could be used if the QCL type(s) did not indicate that the reference RF signal and the positioning reference RF signal have the same average delay only, the same delay spread only, or both the same average delay and the same delay spread. 